


LIBRARY OF CONGRESS. 

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Copyright, 1883, by 
The Lane and Bodley Co, 


Cincinnati, Ohio 


















TO THE READER. 


Upon smelting and smelting plants there exist most 
excellent elementary and exhaustive treatises, of value to 
the student and the accomplished metallurgist, respect » 
ively; but our somewhat extended experience in design - 
ing, erecting, and working smelting plants, has demon= 
strated the necessity for some manual, conveying, in a 
brief manner, a general idea (to investors, and others, 
whom circumstances require to use intelligent judg= 
ment in relation thereto), as to their mode of construe - 
tion and operation; hence this monograph has been 
prepared; but without any claim to systematic or 
thorough scientific treatment . 


LANE & BODLEY CO., 


Per J. M. L. 


Manufacturers of Mining, Milling, Smelting, and Concentration 
Machinery, Steam Engines, Boilers, etc., etc. 


OFFICE AND WORKS: 

Corner John and Water Streets, 
Cincinnati, Ohio, 

U. S. A. 


WESTERN OFFICE: 

Joseph M. Locke, C. E., Manager, 
1252 1st South St, 

Salt Lake City, Utah. 











PRELIMINARY. 


The majority of mankind, including those classed as 


“ well read,” find themselves at a loss when called upon 
to decide questions relating to the metallurgical opera¬ 
tions incidental to utilizing products of our extensive 





gold and silver mining. This results from these opera¬ 


tions being of such a technical character as not to be 


embraced in general experience or reading; we will, 
therefore, briefly state the resume of various methods 
employed by metallurgists to accomplish the results 
sought for; but as this monograph is mainly devoted 

designated “Smelting,” that operation 
ally discussed, and attention especially 
pessary ‘ ‘Plant.” This is a term used to 
.e appliances required for the production 
i. e., the extensive Edgar Thomson 
dth all its appliances for the 
3mer Steel and rolling it into i 
iemer Steel Rail Plant.” 













6 SMELTING PLANTS. 


The ores of metals, as received from the mines, con¬ 
tain, mixed with valuable mineral, more or less useless 
rock, and the metals sought are generally chemically 
combined with other substances; in fact, the metals 
sought for frequently form but a small per cent, of the 
ore as obtained in the mine; for example, in Europe 
copper ores are worked which contain only from two to 
three per cent, of that metal; and what is known with 
us as a fifty-ounce silver ore, is one in which fifty troy 
ounces of silver exist in 2,000 pounds, avordupois, of 
ore, or fifty troy ounces of silver in 29,166f troy ounces 
of ore, otherwise O.y 1 -^ 1 -^ of one per cent, of silver. In 
the case of gold ores, actually worked, the minute per 
cent, is still more marked, often being as small as one- 
hundredth of that above given for silver, to-wit., 

one P er cen ^* 

The ore having been obtained, the problem is to 
separate, in a marketable shape, the metals sought for; 
in cases of gold and silver ores this is frequently accom¬ 
plished by one of the following processes : 

i.—LEECHING PROCESS. 

By washing crushed ore, under favorable circum¬ 
stances, with some solution which will dissolve the 
desired metals, but not the other constituents of the 









SMELTING PLANTS. 


■MM 

7 


ore, then separating the metals from the liquids so used. 
The apparent simplicity of this method is captivating, 
but there are many conditions to be complied with in 
its practical use, generally more than can be satisfied. 


2.—AMALGAMATION, OR MILLING PROCESS 

Consists in intimately mixing crushed ore, under 
favorable circumstances, with quicksilver and water. 
The quicksilver, having a great affinity for gold and 
silver, dissolves those metals, forming a compound, called 
“amalgam,” which, after being separated from the 
mass of exhausted ore, has the quicksilver driven 
off by heat, thus leaving the gold and silver in con¬ 
dition to be melted and cast into bars. This method 
is, in fact, one form of the first, quicksilver being the 
solvent employed. 

3.—SMELTING PROCESS. 

Here we have a different mode of procedure, as the 
rocky portion of the ore, which it is desirable to get rid 
of, is acted upon by mixing the ore with such substances 
(designated “ fluxes ”) as will, with the aid of heat, 
form readily fusible glass, called “slag.” 

The above described mixture of ore and fluxes, which 
should also contain some lead or copper ore, is, with a 































8 


SMELTING PLANTS. 


L 


proper amount of fuel, charged into a smelting furnace 
supplied with a blast; fusion follows, the molten lead 
or copper, having very great affinity for gold and silver, 
absorb into themselves these metals: the fluxes, with 
the foreign matters in the ore, fuse into slag, and being 
of different density from the metals, separate therefrom, 
thus enabling the molten slag and metals to be drawn 
off from the furnace separately; the metals being cast 
into bars are in marketable shape; the subsequent 
separation of the gold, silver, lead, or copper, is gener¬ 
ally conducted by other parties as an independent 
business. The lead mixture is known as “argentif¬ 
erous lead,” but in trade is improperly called “base 
bullion.” 

In practical operations, the slag has a pre-determined 
composition, governed by chemical laws and practical 
experience; it is composed of flint, oxide of iron, and 
lime in certain fixed proportions; therefore, the first 
step is to analyze the ores and fluxes, then, by calcula¬ 
tion, determine what is to be the quantity of the fluxes 
added, that the entire mixture may have the ingre¬ 
dients in proper proportion to form slag of the desired 
composition. Neglect or want of knowledge on this 
point is the most frequent cause of failure. 


i 























ARGENTIFEROUS LEAD SMELTER 


(PLATE 1.) 












































































































SMELTING PLANTS. 


9 


The foregoing general statement will enable one to 

follow intelligently the various steps in the process, 

\ ' 

and understand the “plant” employed, as shown m 
plate I. 

In this case the ore and fluxes are received from a 
railway car onto a platform, the larger pieces being 
passed through the crusher at the platform; the crusher 
being driven by a belt carried underground from the 
engine in the building, the ores, fluxes, and fuel are 
then taken to the “ feed floor,” or second story of the 
main building, which floor is on a level with the “ore 
yard,” on which the crusher platform stands; there they 
are weighed out in proper proportions and thrown 
through the “ feed door ” into the furnace, which opera¬ 
tion is continued as rapidly as the materials are melted 
and taken out at the “ slag floor,” or lower story. 

For a few moments we will ask attention to Plate 
II, representing a furnace with one-half in section, 
that the action within the furnace may be more 
fully understood. The mixed ore, fluxes, and fuel are 
fed into the furnace as previously described, gradually 
settling down through the brick shaft of the furnace 
until they reach where the sides are made of steel 
boxes, called “ water jackets ,” and kept cool by a con- 






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SMELTING PLANTS. 




tinuous supply of cold water; therein the combustion 
takes place, a high heat being obtained by air from 
the blower near the engine, which drives it. The 
blast enters the furnace through pipes called tuyeres, 
at the mouth of which the last of the fuel is entirely 
consumed, the fluxes and foreign matter whilst melting 
unite into slag, the lead separates, carrying with it the 
gold and silver, and settles into the large cavity formed 
in the masonry below the water jackets, and known 
as the “ crucible.” From the bottom of the crucible a 
channel passes diagonally upwards, terminating in a 
bowl in the top of the masonry outside of the water 
jackets, thus forming what is known as the “syphon 
tap;” the fused argentiferous lead passes through this 
syphon tap and is discharged into a “ cooling pot,” from 
which it is ladled into proper moulds forming bars. 
From each bar is cut, b} r a sampling gouge, a small piece; 
all the pieces so cut are subsequently melted together 
and then assayed, thus determining the ounces of gold 
and silver in each ton of the “ base bullion.” 

At the bottom of one of the water jackets is an 
opening, stopped with clay, which is occasionally re¬ 
moved to allow the slag to escape into slag pots (see 
Plate I), where it is allowed to congeal; the top 





























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12 


SMELTING PLANTS. 


with its contents is then wheeled to the edge of the 
yard in front of the furnace, and the cake of slag 
turned out. If any base bullion escaped from the 
furnace with the slag, it is found upon what was 
the lower end of the slag and is readily removed; the 
slag is then thrown over the precipice called the “ slag 
dumpy 

We will now return to the feed floor. The smoke 
and gases, escaping from the materials in the fur¬ 
nace, carry with them vapors and dust rich in lead 
and silver; these are conducted from the top of the fur¬ 
nace by a pipe down on the outside of the building, 
then under the feed floor; here are cone-shaped cham¬ 
bers, with their points downward, in which most of the 
dust and vapors are collected. -From these chambers the 
pipe continues underground to the square ventilating 
stack, then up through it, and sufficiently high to give 
requisite draft; the above mentioned cone-shaped 
chambers are called “ dust chambers ” and the materials 
therein collected “flue dust” which dust is readily 
removed through openings provided at the points of 
the cones. 

Ventilation, about the furnace, between the feed floor 
and slag floor, is important and difficult to obtain, but 






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SMELTING PLANTS. 


13 


in this case it is accomplished by an opening near the 

» 

rear of the furnace, from which opening a flue runs 
under the ore yard to the square ventilating stack. 

An elevator, driven by belts from the engine, is 
found to be convenient for raising bullion for shipment, 
and the flue dust, scraps, etc., to be recharged into the 
furnace. 




















SMELTING PLANTS, 


(for gold, copper, lead, AND SILVER.; 


THE SELECTION OF THEIR SITE 

I — and — 

Adaptation and Equalization of their parts. 


Modern civilization and the advanced state of the 
arts, demand a large supply of metals of all kinds, and, 
after the discovery and development of mines, the 
utilization of the ores became the duty of the metal¬ 
lurgist. These duties are two-fold—those of the chemist 
and engineer. The qualifications of the first are called 
prominently into use in the preliminary steps, deter¬ 
mining the best mode of treatment and subsequent run¬ 
ning of the required plant; but between these two ex¬ 
tremes the qualifications of the engineer come into 













SMELTING PLANTS. 


15 


prominence in selecting a site, planning and con¬ 
structing the details of the plant. 

In the present article we shall presume that the 
characteristics of the ores have been carefully consid¬ 
ered, and smelting found to be the proper method for 
their treatment. 

LOCATION OF PLANT. 

This is often a difficult question to determine, as 
many elements enter into its solution; frequently, the 
error is committed of looking only to suitable ground, 
disregarding the question of transportation of ores, 
fluxes, fuel, etc., to the works, and of product to the 
market, thereby paying indirectly too high a price for 
the true or fancied advantages of conformation of 
ground. In practice it is often found that the disad¬ 
vantages incidental to lack of fall, etc., of locations, 
otherwise desirable, can be overcome by so arranging 
the plant as to make the increased cost of running 
much less than the increased cost of transportation, 
etc., incidental to locating works on more favorable 
ground for their construction ; therefore, as the arrange¬ 
ment of the essential parts of a smelting plant admits 
of great diversity, preference can not be given to any 


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16 


SMELTING PLANTS. 




one form as most desirable under all conditions; in fact, 
an arrangement which would he excellent practice 
in one locality would be exceedingly had in some other 
location, where all, or some of the conditions, are differ¬ 
ent. 

In order to clearly present our ideas upon the impor¬ 
tance of proper arrangement of plant, we shall enume¬ 
rate some of the more prominent data affecting it, 
without any attempt to give them in the order of their 
importance. 

1st. Is the plant to be one of permanence, so as to 
justify expenditures in construction to render future 
running economical ? 

2d. Is there sufficient capital to construct a well 
arranged and built plant, or will it be necessary to, 
depend upon profits to complete the plant ? 

3d. What amount of fall can be obtained for smelter 
at the location ? 

4th. What is the character of the ground to be exca¬ 
vated ? 

5th. In the future will the plant probably require 
enlargement ? 

6th. Will the ores, etc., received be in large or small 
lots, and of uniform or varied character ? 







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SMELTING PLANTS. 


17 


7th. Will ores, fluxes, etc., be sampled prior to being 
received at the smelter, or subsequently ? 

8th. What are the facilities for, and cost of transpor¬ 
tation of machinery from point of manufacture ? 

9th. What are the relative costs of building in iron 
stone, brick, or timber? 

After a determination of conditions 1st and 2d, 
then the important questions are the 3d and 4th; if there 
is fall enough, the arrangement can be : 

I. In three (3) terraces, as designated in Fig. 1. 



A.—Keceiving level. B.—Storage level. C.—Feed floor. 

D.—Slag floor. E.—Slag damp. 

II. With less fall, the first terrace to be dispensed 
with is the top one, by bringing receiving level (A) 
down to that of the storage yard (B), as per Fig. 2. 





































I 



18 SMELTING PLANTS. 



A.—Receiving yard. B.—Storage yard. C.—Feed floor. 
D.—Slag floor. E.—Slag Dump. 


III. In case of still less fall, the matter requires 
more consideration; if the dump fall is dispensed with 
it will require all slags to be elevated and run off into 
a pile, as per Fig. 3. 



A.—Receiving level. B.—Storage yard. C.—Feed floor. 
D.—Slag floor. E.—Slag dump. F.—Elevator. 


IV. Or in case the fall from feed to slag floor (C to 
D) is dispensed with, and the dumps retained, we have 
an arrangement in accordance with Fig. 4. 














































































SMELTING PLANTS. 


19 




: 

iL 

. Jl 

;L D 


A.—Receiving level. B.—Storage yard. C.—Feed floor. 

D.—Slag floor. E.—Slag dump. F.—Elevator. 

f 

In this case, as all fuel, ore, and fluxes, are required 
to be elevated to the feed floor, more hoisting will be 
done than in the preceding case (III); but there will be 
great advantages in cheapness of construction, with 
much more thorough ventilation secured on slag floor. 

And the receiving of ores, etc., mixing charges, tapping 

■> 

slag and lead, all being upon one level, can be more 
thoroughly under the supervision of the foreman. 
These advantages are important, and considerable 
weight should be given them. In cases I, II, and III, 
the character of ground to be excavated, and the amount 
of retaining walls to be built, become considerable fac¬ 
tors in their discussion. 

V. This is where no fall exists, and the plant would 
be arranged as in Fig. 5, which involves the elevation 


* 



































20 


SMELTING PLANTS. 


of all ores, fluxes, fuel, and slag; but has the advanta¬ 
ges stated in IV, of cheapness in construction, thorough 
ventilation, and superior opportunities for the fore¬ 
man looking after receiving ores, making up furnace 
charges, tapping the furnace, and shipping bullion. 



A.—Receiving level. B.—Storage yard. C.—Feed floor. 
D.—Slag floor. E.—Slag dump. F.—Elevator. 


The foregoing advantages are so great as to leave it an 
open question if it is not the best form of smelting plant, 
even in such cases as those where the decreased cost 
of original construction is not of material importance. 
Where a fall exists, it could be utilized in the receiving 
and storage yards and slag dump. 

Having arrived at a decision as to the general 
arrangement, it becomes important to determine the 
sizes and locations of the various machines and appli¬ 
ances composing the plant. Here again the surrounding 
conditions are to be considered. The furnace, being 
the most essential, will first demand attention. After 


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jL' 


SMELTING PLANTS. 


21 


having settled upon its size (at the tuyeres), then the 
distance from the tuyeres up to the feed floor must be 
decided upon. In this matter, be sure height enough is 
allowed, for too much height will be no serious error, 
as the furnace need not be charged to a greater height, 
above the tuyeres, than is necessary; but if the feed floor 
is not sufficiently elevated, which is a very general 
mistake, then there is no effectual remedy. It is advis¬ 
able not to make the distance from tuyeres to feed floor 
less than 12 feet, and in most cases, more is better. A 
lack of fall at locations often induces parties to commit 
this error. In one case, within our knowledge, the 
engineer was overruled in the construction of a large 
works, the distance from the tuyeres to the feed floor 
was diminished, in order to save the fall for dump pur¬ 
poses, consequently, when the furnaces were started, 
the feed doors had to be raised two feet above the feed 
floor, resulting in greatly increased labor in feeding, 
and difficulty in properly spreading the charges as fed 
into the furnaces. 

The size of the blower, crusher, and engine, will 
naturally follow from that of the furnace, but that of 
the boiler will be greatly influenced by what is the 
source of water supply, to-wit.; can the water be ob- 


i 














22 


SMELTING PLANTS. 


tained from a sufficiently elevated source to flow into 
the jackets and the boiler feeder, or will it require 
pumping up from a lower level, in which case, the 
depth the water will have to be raised from will deter¬ 
mine the additional boiler power required; in all 
cases it is desirable to have a boiler capable of fur¬ 
nishing more than the power ordinarily needed, so 
that in case of more power being temporarily desirable, 
or the boiler not being perfectly clean, or the fuel of 
unusually poor quality, no trouble will be experienced ; 
boilers so proportioned require less attention, at the 
same time furnish the necessary amount of power by 
the consumption of less fuel. 

The elevator is not an essential part in cases I and II 
(pages 19, 20 ), but is in III, IV, and V, and desirable 
in all. As to form, preference should be given to that 
known as the “direct hydraulic,” and so extensively 
used in Bessemer Steel Plants; but the ordinary power 
rope elevator is somewhat cheaper and answers all the 
purposes. 

LOCATING THE MACHINERY. 

In this there are several plans, all of which admit 
of more or less modification. 







SMELTING PLANTS. 


23 


1st. Locating boiler and engine at one end of fur¬ 
nace building, with the crusher, blower, and hoister, 
(if a power hoister) so located as to readily receive 
power from the engine by belts, the air being carried 
from the blower to the furnace through metal pipes. 
(See Plan I.) 


Plan I. 


ID 






A- Receiving and crusher platform. B.—Storage yard. C.— Furnace 
building. D.—Slag floor. E.—Slag dump. F.—Elevator. 

G.—Boiler, engine, blower, and pump house. 

Sometimes a line of shafting is carried from the 
engine through the furnace building, and from it power 
is distributed as required; this is convenient, but in 
practice difficulty is experienced in keeping in good 
order a line of shafting so situated. 

2d. Locating boiler and engine back in the storage 
yard, having the crusher close to it, also the blower, 


















24 


SMELTING PLANTS. 


from which the air is transmitted in a metal pipe to 
the furnace ; a hoisting winding apparatus can also be 
placed near the engine, with the elevator rope carried 
overhead to the place where it is to be used. (See 
Plan II.) This arrangement places all machinery near 
the dust and grit from the crusher and handling of the 
ore. 




A. Receiving platform and crusher. B.—Storage yard. C.—Furnace 
building. D.—Slag floor. E.—Slag dump. F.—Elevator. 

Gr.—Boiler, engine and blower house. 

3d. The boiler, engine, blower, and winding machine 
for elevator, altogether placed on the slag dump in 
front of the furnace building (see Plan III); but this is 
a bad arrangement on account of the difficulty of trans¬ 
mitting the power to the crusher, necessarily located 
on the other side of the furnace building. 























25 

1 




A.—Receiving platform and crusher. B.—Storage yard. C.—Furnace 
building. D.—Slag floor. E.—Slag dump. F.—Elevator. 

G.— Boiler, engine, and blower house. 

4th. The boiler to be placed at any convenient 
point, the blower, crusher, and elevator, and pump, 
when used, each to be placed at the most convenient 
point for their use, and to each attach a steam engine 
of sufficient power to work the machine, the steam 



being supplied to all by pipes from the single boiler; 
this arrangement has the advantage of allowing every 
machine to be placed in such position as may be most 
desirable, dispenses with all shafting and belting, but 


is subject to the objection, that the duties of the person 
in charge of machinery is so much distributed that he 
can not watch it all at the same time. 


M 
































26 


SMELTING PLANTS. 


Arrangements of plants are made combining some 
of the features of two or more of the foregoing plans, 
but, in all cases, it is best that full drawings be made 
of a plant prior to its erection; thereby many defects 
in arrangement, and difficulties in details of con¬ 
struction, will be discovered and provided for, thus 
securing a better plant, and, at the same time, saving 
more in construction than the cost of the plans; for 
changes on paper are not as expensive as those in 
wood, brick, stone, or iron. 


























































































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